school me what is the advantage or disadvantage of the number of vanes on a impeller my johnson f9b takes both thanks
Use the 12 Vane. Been all thru this with DepcoPump and my own research. You would not think so but the 12 vane moves more water.
I just replaced the impeller on my stbd engine. I'm going to do the port next but need to order two back-ups first. With the economy affecting the price and supply of everything, I decided to research the few manufacturers that I've used in the past just to get an idea of cost and availability. Any thoughts on quality, durability etc of Jabsco, Johnson, Globe, Sherwood etc? Fresh water, 3 season usage.
Your replacing the impeller or the whole pump? Usually Jabsco impellers go best into Jabsco pumps. Johnson impellers go best into Johnson pumps and so on for Sheerweed. These all use the same neoprene and/or nitrile materials. I don't see any one impeller better or less than the other,, except for one company. Do not install a Globe impeller into a main engine and expect seasonal use with out problems. Now whole pump mfg and designs can be a hard topic that may never be resolved. I despise Sheerweed pumps but not because of their impellers but sheet designs for used on Cummins (and others) engines. Another pump company thankfully can replace this garbage, SeaMax.
Replace your impellers every 2 years, 3 years maximum. But I prefer them done every 2 years in 99% of cases. The small generator impellers I do annually, they're cheap enough and don't last.